1. Field of the Invention
This invention generally relates to duplex electrical receptacles having surge-suppressors for protecting electrical devices plugged into the receptacles from transient line voltage surges and, more particularly, to a replaceable surge-suppressor having an audible failure indicator.
2. Description of Related Art
Electrical receptacles having multiple electrical outlets arranged on so-called power strips or power packs have heretofore been proposed with built-in surge-suppressors operative for protecting electrical devices plugged into the outlets from transient line voltage surges. A typical surge-suppressor comprises a metal oxide varistor. High voltage surges are clamped by the varistor to safer lower voltage levels. A fuse is electrically connected in series with the varistor, and is intended to prevent the varistor from exploding in the event of varistor failure.
Usually, a surge-protected receptacle is flush-mounted with a room wall and, more often than not, is concealed from direct view by being positioned behind a desk or a piece of furniture. In any event, upon failure of the surge-suppressor, the entire receptacle must be replaced, which can be a time- and labor-intensive procedure and, as a result, surge-suppressor failure is often ignored.
Sometimes, the surge-protected receptacle is provided with a pilot light which visually indicates the status of the surge-suppressor. The pilot light is operatively connected to the suppressor. When the pilot light is lit, this indicates that the surge-suppressor is functioning. When the pilot light is extinguished, this indicates that the surge-suppressor is inoperative, and that there is no protection for the electrical device plugged into the receptacle. In those circumstances where the pilot light is concealed from direct view, the extinguishing of the pilot light may not be readily noticed, with the result that, even though the electrical device plugged into the receptacle continues to operate, surge protection has been lost without the operator of the electrical device having been alerted to the loss of surge protection. This could result in damage to the electrical device.